Dental lighting fixture



April- 19, 1932. J. HANSEN DENTAL LIGHTING FIXTURE Filed May 2, 1931 2 Sheets-Sheet 1 INVENTOR ATTORNEY April 19, 1932. J. HANSEN I 1,354,303

DENTAL LIGHTING FIXTURE Filed May 2, 1951 '2 Sheets-Sheet 2 INVENTOR 1 W/yM Patented Apr. 19, 1932 PATENT OFFICE UNITED STATES JASPER HANSEN, OF DECATUR, ILLINOIS, ASSIGNOR TO FARIES MANUFACTURING COMPANY, OF DECATUR, ILLINOIS, A CORPORATION OF ILLINOIS DENTAL LIGHTING FIXTURE Application filed May 2, 1931. Serial No. 534,527.

My invention relates to that class of fixtures which is described in my copending application, Serial N 0. 534,526. In that device the arm which carries the light is extensible, one part telescoping into the other. This necessitates providing a sufiicient amount of slack in the wire which carries the electric current to the lamp to permit the arm to be extended and some means of caring for this slack when the arm is retracted.

My invention has for its object to provide means which will permit the excess orslack of the wire being located inside of the arm.

A further object is to provide means to prevent the excess wire from tangling, regardless of how quickly the telescoping arm is retracted.

My means of accomplishing the foregoing objects may be more readily comprehended by having reference to the accompanying drawings in which Fig. 1 is a side elevation of my improved light, the various positions towhich it may be moved, being indicated by dotted lines;

Fig. 2 is a top or plan View of the same; and

Figs. 3, 4, 5, 6, 7 and, 8 are detail views.

Similar reference numerals refer to similar parts throughout the entire description.

As shown in the drawing, my device is mounted upon a vertical standard 5 which may be secured to any convenient support (not shown) The end 6 of the vertical standard 5 forms a pivot pin upon which is pivotally mounted a member 7. The member 7 has a central opening in which is mounted a disk 8. The disc 8 is provided with suitable clutch members 9 located in notches 10 cut in the peripheral of the disc 8. These members permit the disc to rotate freely in one direction but offer strong frictional resistance to movement in the opposite direction. I provide an arm 11 having a bifurcated end, the forks 12 and 13 of which are secured to the disc 8 by means of a suitable fastening, as shown it is a bolt 14. The arm 11 is formed of suitable tubing, a telescoping arm 15 is slidably mounted in the arm 11. This arm 15 is preferably hexagonal to prevent its rotating upon its axis, a bushing 16, with a hexagonal opening therethrough being fixedly mounted in the end of the arm 11, the arm 15 sliding freely in said opening. The other end 17 of the arm 15 has a spring friction device secured to it so as to hold the arm 15 in the position in which it is placed regardless of its inclination from the horizontal. This device comprises two collars 18 and 19 which carry a plurality of fiat springs 20, the ends 21 of which are held by the collars, the bowed portion 22 frictionally engaging the inner surface of the arm 11. An electric light 23 is secured to a universal joint 24 which is carried by the telescoping arm '15. A stop being-provided to prevent a complete rotation of the lamp and thus avoiding a possible short circuit being caused by twisting the wires 26. These wires-are carried in a suitable insulated cable which is coiled around a rod 27 mounted inside of the arm 11. The end 28 is tapered to the outer end 29 of the rod 27 this insures the wire coiling itself around the rod 27 when the arm 15 is retracted. The natural resiliency of the wire furnishing sufficient springyness to take up the slack no matter how quickly the arm 15 may be retracted and I have found in practice that the tapered end 28 effectually prevents any snarling of the cable. A washer 30 formed preferably of vitrified fiber though other suitable insulation may be used is mounted in the arm 11. I form this washer 30 when fiat slightly larger than the inside diameter of the arm 11 so that when it is mounted in position it must be slightly concave. A keyhole slot 31 is formed in the center of the washer, the larger part of which fits a member 32 to'which the rod 27 is fixedly secured. The device is assembled in the following manner.

The cable is coiled inside the arm 11, the end passing through the opening 31 in the washer 30, the rod 27 is then inserted in the arm 11 passing through the washer 30 until the member 32 reaches the washer. This crowds the cable into the lower portion of the keyhole slot 31 as the member 32 enters the larger portion of said slot. As this member fits tightly in the washer it is necessary to drive it into the opening 31 and this straightens the washer 30 thus firmly anchoring the rod 27 centrally of the arm 11. The friction device mounted on the end of the arm 15 is then inserted into the arm 11. It will, of course, be understood that the cable has first been passed through the arm 15 and the wires 26 connected to the standard socket in the usual manner. The bushing 16 is also slipped over the arm 15 before the friction device is inserted in the arm 11 when the arm 15 is completely telescoped, the bushing is inserted in the end of the tubing or arm 11 and secured firmly in place. This may be done by a pin or in any other desired manner.

\Vhen the arm 15 is extended the cable will uncoil off of the rod 27 sufficiently to accommodate the extension and the friction device will hold the arm in its extended position. hen the operator has finished using the light he may just give it a shove upwardly and the disc will rotate until the arm 11 is sufiiciently elevated when the clutch members will prevent it from coming down though if pulled down it will yield without difiiculty. It will be seen from the foregoing that I have provided a lamp which is adjustable longitudinally of its axis, can be swung laterally and vertically and which also can be rotated upon its own axis, thus making it possible to obtain practically any desired position.

Having described my invention what I regard as new and desire to secure by Letters Patent of the United States, is:

1. In a device of the character described, a light supporting arm formed of a pair of tubes, one of which telescopes the other, the telescoping tube being hexagonal in cross section, a spring friction device carried by said hexagonal tube and slidable in the outer tube, a cable carrying wires for the light and a washer formed of insulating material fixedly mounted inside the inner end of the outer tube, means carried by said washer which permits said cable to freely uncoil ofi' of said means as the hexagonal tube is extended and about which said cable coils when said tube is retracted.

2. In a device of the character described, a light supporting arm formed of a pair of tubes, one of which telescopes the other, the telescoping tube being hexagonal in cross section, a spring friction device carried by said hexagonal tube and slidable in the outer tube, a cable carrying wires for the light and a washer of larger diameter when fiat than the inside of said tube formed of insulating material fixedly mounted inside the inner end of the outer tube, means carried by said washer which permits said cable to freely uncoil off of said means as the hexagonal tube is extended and about which said cable coils when said tube is retracted.

3. In a device of the character described, a light supporting arm formed of a pair of tubes, one of which telescopes the other, the

telescoping tube being hexagonal in cross sec tion, a spring friction device carried by said hexagonal tube and slidable in the outer tube, a cable carrying wires for the light and a washer formed of insulating material fixedly mounted inside the inner end of the outer tube, there being a key hole slot in said washer, the cable passing through the smaller part of said slot and rod supporting means which tightly fits the larger portion of said slot mounted therein, a rod fixedly secured thereto which extends freely through said outer tube, said rod having a tapered free end which permits said cable to freely uncoil off of said rod when said tube is extended.

4. In a device of the character described, a light supporting arm formed of a pair of tubes, one of which telescopes the other, the telescoping tube being hexagonal in cross section, a spring friction device carried by said hexagonal tube and slidable in the outer tube, a cable carrying wires for the light and a washer formed of insulating material fixedly mounted inside the inner end of the outer tube, a rod carried by said washer which extends into said telescoping tube and which permits said cable to freely uncoil off of said rod as the hexagonal tube is extended and about which said cable coils when said tube is retracted.

JASPER HANSEN. 

